Whence minority rule?

Well, no science post today.  We're spending too much time watching live footage from Egypt. Not only do we, as Americans and people fortunate enough to live in a democracy, sympathize with the protestors, but our daughter is now living and teaching music in a conservatory in Palestine, amidst people for whom occupation is a constant fact of life (and we sit here smugly, the occupiers of North America, who put its prior indigenous inhabitants essentially in permanent refugee camps).

But in addition to the sense of unfairness about human politics in so many places, this leads us to muse about how it is that human societies manage to establish minority rule, often cruel minority rule.  How is it that a small number of people can control the lives of a much larger number?

The evolutionary basis of inequality is perhaps interesting but not the answer.  Social hierarchies cannot be put down to the leaders' better intelligence or belligerence genes.  Even if dominance were genetic, its evolution over countless generations in small demes would largely have fixed the responsible genes, so that most positions in the dominance hierarchy would be due to chance or something other than genes. 

Social pyramids are something different. One person leverages several others by dint of personality or resources or something, and they in turn leverage a larger number.  Those at the top control information, resources, education, and so on.  They then control acculturation, beliefs (including the belief that the boss deserves to be boss because of some religious or political ideology), and so on.

But these are descriptions of what happens, even in democracies.  Yet it seems inevitable regardless of ideology, as communist countries surely and clearly showed.  Hierarchies are of all sorts, some more rigid than others, but they are found at all levels of society.  It's easy, one might say, to see why organizations from families to teams to clubs to governments function only when they have  leaders and followers, but again description is not what's interesting to us from a biological point of view.

From that point of view, how do minorities manage to control majorities?  Is the answer to be found in physiology or genetics in any useful sense?  Or is it, as the founders of modern (and hence pre-postmodern) social scientists argued, something that must be explained in terms of social, rather than biological facts--that is, that society's structures may be manned by biological organisms, but the nature and evolution of those structures has its own properties independent of the biological details: hierarchies can exist in any population with any set of genotypes.  Are there some properties or principles by which such social facts can be explained, and if so are they like 'laws of Nature'?  Could it be otherwise, and if not, why?

These are thoughts that come to us as we watch the struggles now going on in the Middle East.

Causes of aggressive behavior found?

Here's an interesting juxtaposition of stories about causes of aggressive behavior in mice.  A story on the BBC web site, reporting on a paper in the Proceedings of the National Academy of Sciences, suggests that the microbiome in the gut of some lab mice is responsible for their adventurousness.   

The teeming trillions of bacteria in the digestive tracts of mice have been shown to affect the animals' brain development and behaviour.

Mice bred in sterile environments without these "gut flora" were seen to be more adventurous and less anxious than mice with normal gut flora.

The authors compared gene expression profiles in the brains of mice raised in the germ free environment with those in the non-sterile environment and found consistent differences in the levels of expression of 50 genes.  The authors conclude "our results suggest that the microbial colonization process initiates signaling mechanisms that affect neuronal circuits involved in motor control and anxiety behavior."

In situ hybridization results showing Grb10 inactivated
 in mouse on right.

In contrast, a paper in Nature, as reported in the New York Times, suggests that altering a specific gene boosts aggressive behavior in mice.  The Times says

For some genes, either the father’s version or the mother’s version is active, but not both. Which version of the gene works is determined before conception, as the sperm and egg are developing, in a process called imprinting. By mimicking that process in the lab, and turning off a gene in mice, scientists have produced a change in social dominance behavior. In laboratory tests, mice with the paternal version of the gene known as Grb10 inactivated were more aggressive in their behavior...

These papers don't necessarily contradict each other, although it doesn't look like Grb10 is one of the 50 genes whose expression level is affected by microbes in the gut.  If both results are real, this suggests that, like many traits, there may be multiple paths to aggressive behavior.  And that there is no single allele 'for' a trait like this.  That wouldn't be a surprise.

On the other hand, either or both results might well be no more than speculation, as many science stories these days.  The amount of basically wild speculation, picked up by the media as if substantial or well-anchored scientifically, continues to be high.  With 24/7 media, and a public (and scientists) hungry for simple stories, reinforces this.

Of course, there is no reason to doubt that anything might affect anything else, so the main point of responsible science is to balance what is found so far with might be found or might be true or correlated with what is found.  If that were more predominant, stories like these, that are certainly interesting, might be more likely to be viewed as science rather than stories.

CoE

This month's Carnival of Evolution is up.  And Darwin is very appreciative indeed.

Lost and found -- Breaking Dollo's Law

It has long been thought that once a species loses a trait, that trait is gone forever.  The loss can't be reversed.  This is so well-accepted that it's risen to the status of a law of nature, Dollo's Law.  Dollo was a Belgian paleontologist working around the turn of the last century, and as he put it,  "An organism is unable to return, even partially, to a previous stage already realized in the ranks of its ancestors."  So, for example, according to Dollo's Law, we have lost the tail our ancestors had, and we won't regain it, reptiles that have made the transition from egg-laying to giving birth to live offspring can't go back, and so on.

From the BBC

But laws are made to be broken, and the idea that life follows 'laws' the way gravity and chemistry do is tenuous at best.  In this case, Dollo's 'Law' is currently under challenge.  A paper published online in Evolution on Jan 27, and discussed on the BBC website, describes the re-evolution of mandibular teeth in frogs after more than 200 million years.  Recent reports of exceptions to the irreversibility principle -- wings lost and regained in stick insects, the re-evolution of coiling in snail shells, re-evolved ocelli in cave crickets, wings in water spiders, and so forth -- have been called into question for methodological reasons, but the re-evolution of frogs teeth and other examples look pretty solid.  As Wiens concludes,

The results presented here offer an incontrovertible phylogenetic example of trait re-evolution, showing that mandibular teeth were lost in the ancestor of all living frogs and then re-evolved in the hemiphractid species G. guentheri. The alternate hypothesis, that mandibular teeth were lost independently in each of the dozens of lineages leading up to G. guentheri, is statistically unsupported and seems incredibly unlikely. Although the hypothesis that G. guentheri re-evolved mandibular teeth may be unsurprising to experts in amphibian anatomy, this compelling example has been ignored in the recent literature on Dollo's law. Further, this example is made remarkable by the application of a time scale for this event: mandibular teeth were absent for at least 225 million years (and likely much longer) before being regained.

Another example of an exception to Dollo's Law is described by Lynch and Wagner in the Jan 2010 issue of Evolution.  They present evidence for the re-evolution of oviparity, or egg laying, in "Old World sand boas in the genus Eryx nearly 60 million years after the initial boid transition to viviparity" based on a phylogenetic analysis of genetic data from boid snakes and other related groups.  In addition to the statistical support for re-evolution, they note that morphological evidence includes the fact that, like live born boas, the hatchlings of the "oviparous Eryx lack an egg-tooth providing independent evidence that oviparity is a derived state in these species."  And, the shells of the boas that have re-evolved oviparity are extremely thin compared with the shells of other boas, suggesting that the structure of the eggshell re-evolved as well.

The argument over whether Dollo's Law can be violated may primarily reflect the way we classify species and think about phylogenies.  As Wiens says,

...the observation that most well-documented cases of trait re-evolution occur after a period of trait loss of greater than 15 million years (Table 2) may also reflect methodological bias. A complex structure that re-evolves may need to be absent for tens of millions of years before its re-acquisition can be confidently distinguished from multiple losses (e.g., given typical diversification rates, this period of time may be needed for a group to diversify enough to have species nested deep in the phylogeny). Yet, if the gain of lost traits is possible, a consideration of the underlying genetics suggests that it should be much more likely soon after the trait is lost (Marshall et al. 1994). Thus, trait re-evolution may actually be hardest to detect under the conditions when it is most likely to occur, raising the question of whether trait re-evolution might be more widespread but frequently undetected due to methodological biases.

So, how is the re-evolution of a trait explained genetically?  Weins suggests that the fact that G. Guentheri still have teeth in their upper jaw facilitates the repositioning of teeth to the lower jaw.  The structural genes are there, they just need to be recruited for expression in a different place.  Generally, this is not very perplexing.  Single gene expression changes can lead to signaling environments that, in relevant tissues, can induce cascades of patterning-gene interactions that produce structures like teeth.

Indeed, the normal tissue is not required.  There are mouse and human examples in which hair or teeth grow where the other normally does.  Ovarian teratomas are disorganized tumor-like structures of disorganized embryos that, as was known even in the early 1800's (and cited by Darwin), developed hair and teeth (even chicks do not have enamel genes, but teeth can be induced to form by genetically similar processes as hair or feathers, and transgenic expression of some environment-preparing genes in embryonic chick jaws can lead to tooth-like structures).

Dental formulas (numbers and shapes of teeth in upper and lower jaws) and hair or coloration patterns can come and go for similar reasons.  In many cases, the genetic change can be a modification of existing genes and tissues.  Similar dental formulas have evolved numerous times in vertebrates.  In others, there are different pathways to similar outcomes.  This is what happens in some selection experiments, and seems, if we recall correctly, to be the case with ocelli in insects.  But the overall pathways are presumably rather simple, or the different activations activate similar pathways that are conserved because they are still doing something.  In the frogs, they're making teeth in the upper jaw, a tissue histologically similar to lower jaws.

The point here is not that reversals are trivial or uninteresting, but they are explicable when they occur.  However, highly organized or complex structures are unlikely to recur after too long of divergence.  If we re-evolved, say, swimming anatomy it would not likely be the same as what is found in fish.  Indeed, that is what whales did, and they swim by up and down motion rather than the side to side motion of fish, because their mechanism is anatomically different.

Again, these instances are interesting, and perhaps most interesting is that even before the genetic age anyone should have suggested, much less canonized, 'laws' about how evolution works.  At most they are statistical generalizations that, in genetic terms, relate to the likelihood of the same genetic mechanism re-evolving.

The hen keeps laying (American education shortfalls, continued)

A new survey of high school science teachers, reported in Science (Berkman and Plutzer, Jan 28, 2011, pages 404-405), and described here, shows that many high school teachers do not teach the scientific method or approach it very well in the context of the 'debate' between evolution and creationism.  Many teachers teach outright creationism, while about 60% hedge their bets about the subject.

The authors express it this way:

Creationism has lost every major U.S. federal court case for the past 40 years, and state curricular standards have improved....But considerable research suggests that supporters of evolution, scienfitic methods, and reason itself are losing battles in America's classroom, where instruction in evolutionary biology 'has been absent, cursory, or fraught with misinformation'.

Berkman and Plutzer, Science

We know there is a problem of under-educated teachers generally, low rigor and low admission standards in schools of education, low status and low pay in the jobs.  We know American kids are not getting nearly the rigorous level of training and work ethic that they may need in the future, given what is happening in other nations and the increasingly technological nature of global society.

As scientists, we can't react except with concern about the thin training in evolutionary biology that US students are getting.  But there are two things that all of us should ask, that might make it seem a less dismal situation than it seems.

1.  First, how much does it matter?  The senior generation in this country (of which we're a part) were trained without much, or even specifically with no, high school evolutionary training.  For various reasons, including the pressure from fundamentalist Christian (or so they self-describe, though they may not have read even the Sermon on the Mount which tells what Christians should be about in their lives), evolution was simply omitted from texts.  Even some introductory college Biology courses had relatively little evolution--a chapter, say, along with anatomy, classification, basic physiology, Mendelian genetics, and so on.

Yet this same generation is responsible for what amounts to a massive gain in knowledge across the life sciences, including evolution.  So is our concern about high schools more than just our taking sides in the cultural battle now under way between the 'left' and 'right'?  Does it really matter if most people don't believe in evolution?  For those who need to know or use evolutionary perspectives, things are motoring along very well these days.

2.  Secondly, some people choose to opt out of a purely material, experimental, empirical view of the world.  They depend instead on mysticism, externally derived answers, reassuring dogma, or the comfort of the tribalism of the right.  If that's how they wish to live their lives, and they don't want their kids exposed to what they object to in these very fundamental worldview areas, so what?  Why not recognize that this is the 'age of science' only in some areas of life, for many people?  Wouldn't it be just as good, in this particular sense, to insist that, at least, high school science teachers understood their biology itself?  The things that people need to know about, like how genes work, how infectious organisms work, the diversity of living Nature, structures of human bodies and the nature of plants, etc.

Where are the teachers?
In our Honors class of 19 bright, thoughtful students last fall, in discussing this subject, the students all nodded in agreement as we pointed out the failure of our educational system (some of which they, as college seniors, had experienced only a few years earlier).

Then we asked:  "OK then, so how many of you are going into teaching as your profession?"

The silence was deafening.  The brightest students just aren't going to be teachers.

Whose fault?
It is too easy to feel self-righteous and rue the absence of evolution in school curricula.  But stepping back from our legitimate emotional engagement with the idea that the truth, the whole truth, as seen from the scientific worldview should be taught, suggests that the debate is about other things in our culture than whether the general public really needs to understand evolution as we scientists see it.

After all, within our own families, we have to make up at home for what the less than competent teachers do to or for our kids in all the subjects they are taught.   There doesn't seem to be any legitimate empirical doubt that evolution is a fact of and about life.  Fully educated people should realize that.  But you can live perfectly well without it, as our benighted population shows, and for many the comfort of answers is worth all the truth that Darwin ever wrote.

At least, this is one way to ponder the strangeness of this persistent issue.

Americans lay another egg in science education!

We've posted a number of times before about our educational system.  Here's a blurb from another story on the subject in the New York Times. 

On the most recent nationwide science test, about a third of fourth graders and a fifth of high school seniors scored at or above the level the federal Department of Education calls proficient, according to results released on Tuesday.

 And, a new book, discussed at length again in the NYTimes,

“Academically Adrift: Limited Learning on College Campuses” (University of Chicago Press) by a professor at New York University and another at the University of Virginia, attempts to answer questions [about how much students learn and how they spend their time] in a systematic way — and, as its title suggests, its findings suggest reason for concern.

In the book, and in an accompanying study being released Tuesday, the authors followed more than 2,300 undergraduates at two dozen universities, and concluded that 45 percent “demonstrated no significant gains in critical thinking, analytical reasoning, and written communications during the first two years of college.”

So, we conclude that Americans hardly do any studying, hardly learn anything in college, and can hardly read and write when they graduate from high school.  

Of course, that's an exaggeration, but when our noble society can't agree that climate is changing anomalously, or whether vaccines cause autism, or whether evolution occurred, then it's time to take the problem seriously.  The idea that the wealthiest country at any given time is vulnerable to becoming lazy and self-satisfied is not exactly new.  It was written about even by Romans at the height of the Roman Empire (e.g., in satires by Juvenal, at about 115 AD).

Now, universities are dropping programs that 'don't pay', while pouring money into the 'real' subjects like science while visions of overhead dance in their heads.

We recently saw that to qualify as a teacher in Scandinavian countries, you must graduate in the top third of your university class.  By contrast, who do you think populates our schools of education?

We need to insist that students actually do work and come to class, we must be able to fail them if they don't, to stop having students evaluate whether they 'like' our classes, and to have teacher trainees learn more about science than about how to make science bulletin boards.  We need to de-emphasize the precious 'research' that we flatter ourselves is so important, and return faculty to a concentration on teaching.  And if we can afford 90" TVs for every bathroom in the house, we can afford to pay more taxes to pay teachers enough to encourage good students to become them.  There needs to be a sense of seriousness about this, because in case you haven't noticed, improving K-12 will take 13 years to bear fruit!

Just because a society is technological or scientific doesn't guarantee that it will be a good society, and the history of empires suggests otherwise.  But the odds would at least favor a better quality of life for its citizens.  Maybe if research scientists weren't paid so munificently to do incremental, me-too work, and teachers were paid more to build our capability future, these problems would be ameliorated.

But probably not.  Probably, we are so used to our luxuries that we will let ourselves sink slowly into history.

A big congratulations to Holly!

We want to post a brief message of congratulations to our great co-conspirator on MT, Holly Dunsworth. She has just taken a faculty position at the University of Rhode Island. We wish her well and hope, of course, that she'll continue to have the time to make her very interesting, insightful, and amusing contributions to these conversations.